Interference from external magnetic fields is a serious problem in semiconductor devices that include magnetic materials, such as magnetoresistive random access memory (hereinafter referred to as “MRAM”) devices, or the like. Typically, such devices utilize the orientation of a magnetization vector for device operation. In MRAM devices, the stability of the nonvolatile memory state, the repeatability of the read/write cycles, and the memory element-to-element switching field uniformity are three of the most important aspects of its design characteristics. These characteristics depend on the behavior and properties of the magnetization vector.
Storing data in a MRAM device is accomplished by applying magnetic fields and causing a magnetic material in the MRAM device to be magnetized into one of two possible magnetization states. Recalling data is accomplished by sensing the resistive differences in the MRAM device between the two states. The magnetic fields for writing, or imparting a particular magnetization orientation to the magnetic material, are created by passing currents through conductive lines external to the magnetic structure or through the magnetic structures themselves.
If a magnetic field is applied to a MRAM device during writing, then the total field incident to the MRAM device may be less than that required for writing. This condition can cause programming errors. In addition, a typical MRAM architecture has multiple bits that are exposed to magnetic fields when one MRAM device is programmed. These one-half selected MRAM devices are particularly sensitive to unintended programming from an external magnetic field. Further, if the magnetic field is large enough, MRAM devices may be unintentionally switched by the external magnetic field even in the absence of a programming current.
One approach to decrease the effects of magnetic field interference is to magnetically shield the electronic circuit components. Conventional magnetic shielding solutions are often too expensive and not easily integrated with the MRAM devices.
In view of the foregoing, it is desirable to provide a semiconductor device with improved shielding. Furthermore, it is also desirable to provide a method for fabricating such magnetically shielded semiconductor devices that is cost effective and compatible with logic fabrication stages. Furthermore, other desirable features and characteristics will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and this background.